[WIP]Implement musig for jubjub

Cargo.toml

@@ -113,17 +113,18 @@ path = 'demo/cli/src/main.rs'
 members = [
     "core/bellman-verifier",
     "core/crypto",
-    "demo/cli",    
+    "demo/cli",
     "core/jubjub",
     "core/pairing",
     "core/primitives",
     "core/proofs",
     "runtime",
     "core/keys",
+    "core/musig",
     "modules/indices",
     "modules/executive",
 ]
 exclude = [
-    "runtime/wasm",   
-    "demo/wasm-utils", 
+    "runtime/wasm",
+    "demo/wasm-utils",
 ]

core/musig/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "musig"
+version = "0.1.0"
+authors = ["Osuke Sudo <[email protected]>"]
+edition = "2018"
+
+[dependencies]
+jubjub = { path = "../jubjub" }
+rand = { version = "0.6.0" }
+failure = { version = "^0.1.1", default-features = false }
+merlin = "1"

core/musig/src/lib.rs

@@ -0,0 +1,134 @@
+// This file is based on https://github.com/w3f/schnorrkel/blob/master/src/musig.rs
+
+use jubjub::{
+    curve::{
+        FixedGenerators,
+        JubjubEngine,
+        JubjubParams,
+        Unknown,
+        PrimeOrder,
+        edwards::Point
+        },
+    redjubjub::{
+        PrivateKey,
+        PublicKey,
+        Signature,
+    }
+};
+use std::collections::BTreeMap;
+use merlin::Transcript;
+
+pub trait TranscriptProtocol {}
+impl TranscriptProtocol for Transcript {}
+
+const COMMITMENT_SIZE: usize = 32;
+
+pub struct Commitment(pub [u8; COMMITMENT_SIZE]);
+
+impl Commitment {
+    fn for_r() -> Commitment {
+        unimplemented!();
+    }
+}
+
+pub struct KeyPair<E: JubjubEngine> {
+    pub secret: PrivateKey<E>,
+    pub public: PublicKey<E>,
+}
+
+enum CoR<E: JubjubEngine> {
+    Commit(Commitment),                 // H(R_i)
+    Reveal{ R: Point<E, PrimeOrder>},   // R_i
+    Cosigned { s: E::Fs },              // s_i extracted from Cosignature type
+    Collect { R: Point<E, PrimeOrder>, s: E::Fs },
+}
+
+impl<E: JubjubEngine> CoR<E> {
+    fn set_revealsed(&mut self) {
+        unimplemented!();
+    }
+
+    fn set_cosigned(&mut self, s: E::Fs) -> Result<(), &'static str> {
+        unimplemented!();
+    }
+}
+
+/// Schnorr multi-signature (MuSig) container generic over its session types
+pub struct MuSig<T: TranscriptProtocol, S, E: JubjubEngine> {
+    t: T,
+    Rs: BTreeMap<PublicKey<E>, CoR<E>>,
+    stage: S
+}
+
+impl<T: TranscriptProtocol, S, E: JubjubEngine> MuSig<T, S, E> {
+
+}
+
+/// Commitment stage for cosigner's `R` values
+pub struct CommitStage<'k, E: JubjubEngine> {
+    keypair: &'k KeyPair<E>,
+    r_me: E::Fs,
+    R_me: Point<E, PrimeOrder>,
+}
+
+impl<'k, T: TranscriptProtocol, E: JubjubEngine> MuSig<T, CommitStage<'k, E>, E> {
+    /// Our commitment to our `R` to send to all other cosigners
+    pub fn our_commitment(&self) -> Commitment {
+        unimplemented!();
+    }
+
+    /// Add a new cosigner's public key and associated `R` bypassing our commiement phase.
+    pub fn add_thier_commitment(&mut self, them: PublicKey<E>, theirs: Commitment) -> Result<(), &'static str> {
+        unimplemented!();
+    }
+
+    /// Commit to reveal phase transition.
+    pub fn reveal_stage(self) -> MuSig<T, RevealStage<'k, E>, E> {
+        unimplemented!();
+    }
+}
+
+/// Reveal stage for cosigner's `R` values
+pub struct RevealStage<'k, E: JubjubEngine> {
+    keypair: &'k KeyPair<E>,
+    r_me: E::Fs,
+    R_me: Point<E, PrimeOrder>,
+}
+
+/// Revealed `R_i` values shared between cosigners during signing
+pub struct Reveal(pub [u8; 32]);
+
+impl<'k, T: TranscriptProtocol, E: JubjubEngine> MuSig<T, RevealStage<'k, E>, E> {
+    /// Reveal our `R` contribution to send to all other cosigners
+    pub fn our_reveal(&self) -> Reveal {
+        unimplemented!();
+    }
+}
+
+/// Final cosining stage collection
+pub struct CosignStage<E: JubjubEngine> {
+    /// Collective `R` value
+    R: Point<E, PrimeOrder>,
+    /// Our `s` contribution
+    s_me: E::Fs,
+}
+
+/// Cosignatures shared between cosigners
+pub  struct Cosignature(pub [u8; 32]);
+
+impl<T: TranscriptProtocol, E: JubjubEngine> MuSig<T, CosignStage<E>, E> {
+    /// Reveals our signature contribution
+    pub fn our_cosignature(&self) -> Cosignature {
+        unimplemented!();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_multi_sig() {
+
+    }
+}

demo/wasm-utils/Cargo.toml

@@ -55,4 +55,3 @@ rev = "7a5b5fc99ae483a0043db7547fb79a6fa44b88a9"
 [profile.release]
 # Tell `rustc` to optimize for small code size.
 opt-level = "s"
-